Species: Caloplaca decipiens
Photos: On city centre wall. Dublin, Ireland.
Identification confirmed by Alan Silverside (from photographs)
Small light-yellow to brownish-orange thallus, centre darker, often disintegrates. Long convex, +/- distinct lobes with palmate tips, inner lobes with granular orange-yellow soredia.
K+ crimson / purple.
Occurs on mortar, tombstones and nutrient-rich limestone.
Caloplaca decipiens on wall in Dublin. January 2009